Confused!!

Sarah
So am 35 year old. & the harmony test results came back & I was low risk & everything look fine. 
However the sequential blood test results can back VERY high risk in trisomy 18!! It's 1:5 
Don't know which one to believe it's devastating since I heard that number. 
I guess I will just go with the amnio just to get peace of mind for rest of pregnancy :(